commons -lang(2) RandomStringUtils RandomUtils

上一篇是StringUtils 链接http://www.cnblogs.com/tele-share/p/8060129.html

1.RandomStringUtils

1.1模拟实现random(count,str);

     //模拟实现random(5,"helloworld")
     public static String getRandomString(int count,String str) {
         if(str != null) {
             if(!StringUtils.isBlank(str)) {
                 if(count <= 0) {
                     return "";
                 }
                 char[] charArray = str.toCharArray();
                     int index;
                     char[] newArray = new char[count];
                     for(int i=0;i<count;i++) {
                          index = RandomUtils.nextInt(0,charArray.length);
                          newArray[i] = str.charAt(index);
                     }
                     return new String(newArray);
             }
         }
         return null;
     }

1.2模拟实现randomAlphanumeric(字母与数字混合,可能没有数字)

 //模拟实现randomAlphanumeric(字母与数字混合)
     public static String getRandomAlphanumeric(int count) {
         if(count <=0) {
             return "";
         }
         String letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
         int number = RandomUtils.nextInt(0,100000);
         String str = letters + number;
         return getRandomString(count, str);
     }

1.3模拟实现可以指定数字个数的randomAlphanumeric

     //指定数字的个数
     public static String getRandomAlphanumeric(int count,int numbers) {
         if(count <=0 || numbers <=0) {
             return "";
         }
         //纯数字
         if(numbers>=count) {
             return RandomStringUtils.randomNumeric(numbers);
         }
         String letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
         String str = RandomStringUtils.random(count-numbers, letters) + RandomStringUtils.randomNumeric(numbers);
         //打乱位置
         char[] charArray = str.toCharArray();
         List<Character> list = new ArrayList<Character>();
         for (Character character : charArray) {
             list.add(character);
         }
         Collections.shuffle(list);
         for(int i=0;i<list.size();i++) {
             charArray[i] = list.get(i);
         }
         return new String(charArray);
     }
     

总结:RandomStringUtils中的方法可以用于生成随机的验证字符串

2.RandomUtils

这个类感觉与java.util包下的Random类差别不大,还是那几个类似的方法(注意左闭右开)

相比较来说还是RandomStringUtils用处更多一点